#include<iostream>
#include<vector>
#include<queue>
#include<cstring>
#include<cmath>
#include<map>
#include<ctime>
#include<set>
#include<cstdio>
#include<algorithm>
#define debug(a) cout<<#a<<"="<<a<<endl;
using namespace std;
const int maxn=2e5+1000;
typedef int LL;
inline LL read(){LL x=0,f=1;char ch=getchar();	while (!isdigit(ch)){if (ch=='-') f=-1;ch=getchar();}while (isdigit(ch)){x=x*10+ch-48;ch=getchar();}
return x*f;}
LL a[110];
LL dp[maxn];
int main(void){
   cin.tie(0);std::ios::sync_with_stdio(false);
   LL n;cin>>n;
   LL sum=0;
   for(LL i=1;i<=n;i++) cin>>a[i],sum+=a[i];
   if(sum&1){
      cout<<"0"<<"\n";
      return 0;
   }
   sum/=2;
   dp[0]=1;
   for(LL i=1;i<=n;i++){
      for(LL j=sum;j>=a[i];j--){
          dp[j]|=dp[j-a[i]];
      }
   }
   if(!dp[sum]){
      cout<<"0"<<"\n";return 0;
   }
   cout<<"1"<<"\n";
   for(LL p=1;p<=n;p++){
      LL d=sum*2-a[p];
      if( (a[p]&1)||(!dp[d/2]) ){
         cout<<p<<"\n";
         break;
      }
   }
   return 0;
}
